Automatic slack-adjuster for brakes.



INVENIOH PATENTED JULY 23, 1907.

8) I I 0mm R. F. HAMILTON. AUTOMATIC SLACK ADJUSTER FOR BRAKES.

APPLICATION FILED JAN. 26. 1907.

WITNESSES:

1n: uvmus PETERS c RICHARD F. HAMILTQN, OF NEW YORK, N. Y.

AUTOMATIC SLACK-ADJUSTER FOR BRAKES.

Specification of Letters Patent.

Patented July as, 1907.

Application filed January 26,1907 Serial No. 354,223,

To all whom it may concern:

Be it known that I, RICHARD F. HAMILTON, a citizen of the United States, and a resident of the borough of Manhattan, city, county, and State of New York, have invented certain new and useful Improvements in Automatic Slack-Adjusters for Brakes, of which the following is a specification.

My invention relates to automatic slack adjusters for power brakes and particularly railroad air brakes.

The object of my invention is to simplify devices of this character, and specifically to use a single adjuster for taking up the slack of the brakes at both ends of the car, and to do this without the use of any propelling spring beyond the ordinary release spring contained in the brake cylinder.

In the preferred form of my invention, the fulcrums of the dead levers and the automatic slack adjuster are secured to a suitable part of the car body and not to the truck bolsters as in the construction generally employed.

Another important advantage which I had in view in devising my invention is to take up the entire slack or lost motion caused by the wear of the brake shoes, by a single application of the braking power either by hand or air, instead of only taking up a fraction of such lost motion at each application of the brakes.

These and other features of my invention will more fully appear in the description following hereinafter.

Reference is to be had to the accompanying drawings, in which Figure 1 is a diagrammatic view of the entire mechanism; Fig. 2 is a detail view of the slack adjuster and its connections drawn upon an enlarged scale; Fig. 3 is a top view of the slack adjuster; and Fig. 4 is a detail view showing a different way of connecting the slack adjuster, with parts broken away.

A indicates the brake beams with brake shoes A; B the dead levers; C the live levers; D the bottom rods connecting each live lever with the corresponding dead lever; E and F, cylinder levers connected with the live levers by top rods G; H the tie rod connecting the two. cylinder levers; and .T the brake cylinder containing the release spring I and the piston P, the rod J of which is pivotally connected with the cylinder lever E. These parts may be constructed in substantially the usual way, but I prefer to have the fulcrum B of the dead lever secured to the car bolster or car body and not to the truck bolster as it is generstand on a curve. K is a special hand brake lever fulcruined on the car body at K and connected with hand brake mechanism L at each end of the car. This lever is further connected by a slack connection, such as a chain M, with the pin N, which connects the piston rod P with the cylinder lever E.

The pin N travels in a slot 0 at one end of a reach rod 0 the other end of which is connected with a slide 0 containing the movable pawl or dog P. A spring P engages said dog which together with the slide 0 can move toward the left on the take up rod Q, but when the slide moves toward the right the dog P will grip the take up rod and move it in the same direction. The take up rod is guided in brackets R or other supports which I prefer to arrange on the car body, and is connected with the cylinder lever F. A main pawl or dog S abutting against a stationary part S and under the influence of a spring S allows the take up rod to move from left to right, but holds it against movement in the opposite direction. Any suitable construction of pawl or dog may be employed which will perform the functions above described. The dogs P and S may be brought by hand into a position perpendicular to the take up rod Q, so as to allow this rod to be adjusted for a proper operation, when the car leaves the shop. The said dogs are perforated for the passage of the take up rod through them.

The length of the slot 0 is equal to the normal travel of the piston J Thus in the normal operation of the device the reach red 0 will remain stationary. After the brake shoes A have worn, a longer travel of the piston will be required to apply the brakes, and to the extent that the piston exceeds its normal travel (the length of the slot 0) the reach rod 0 will be carried to the left with the piston, the pawl P slipping over the take up rod Q which the pawl S holds against any accidental motion toward the left. When the piston J returns under the influence of the release spring J, the pawl P being engaged by the end of the reach rod 0, will grip the take up rod Q and thus the take up rod is moved toward the right with the reach rod, thereby shifting the fulcrum of the cylinder lever F toward the right, and taking up the slack in the entire lever mechanism, at both ends of the car. The take up rod will then remain in this new position until the brake shoes have worn again, when the adjusting operation described above will be repeated automatically. Whenever any excess slack exists in the lever mechanism, it will be taken up entirely at the next release of the brakes. The slack adjustment will be effected in the same manner whether the brakes be applied by air or by hand, since in either event the reach rod 0 will be actuated if the pin N has an excess travel.

The device is very simple, requiring but few working parts in addition to the ordinary air-brake mechanism. The release spring J is given the additional lever E should be rigid with the piston rod.

' gitudinal slot of the lever.

function of moving the reach rod 0 to the right if the piston exceeds its normal travel, and while I prefer this simple arrangement, an additional spring T hav-' ing the same tendency might be placed on the take up .rod Q between the slide 0 and a stationary bracket R, or an equivalent spring might be connected with the reach rod at some other point.

The slack adjuster is operated by the pin N which in the particular construction so far described is rigid with the piston rod J and forms part thereof. It is not absolutely essential, however, that this pin which connects the piston rod J pivotally with the cylinder Thus in Fig. 4 the connecting pin N is received not only in the slot 0 but in a slot J of the piston rod J Thus when the brakes are applied by air the'operationwill be the same as in the form of my invention first described.

The hand brake lever K-has aslack connection K either with the pin N as in the first form of my invention, or, as shown, with some other portioiiof the cylinder lever E; This cylinder levermay be rigidly connected with the pin N, or the pin may be received in a lon- In this second'form of my invention, the application of the brakes by hand will leave the piston rod'J and piston J stationary, so that the spring J will not oppose anyresistance to the movement of the brake mechanism. The slack adjuster Will, however, be operated through the action of the to be overcome is that of the usual release spring.

pin N upon the reach rod 0, in tliesame manner as hereinbefore described.

In the second form of my invention, a separate spring (such as indicated at T) must be used to move the reach rod to the right. The end walls of the slot O form engaging surfaces or stops between which the pin N moves, the distance between said' surfaces corresponding to the normal travel of the piston .l. The arrangement might be reversed, that is, the reach rod 0 might be provided with a pin located between two engaging surfaces on the cylinder lever E or on the piston rod J" and such reversal I consider an equivalent which I desire to be understood as covered by the claims.

My slack adjuster maintains a uniform maximum efliciency of the brake under all conditions. In the preferred form of my invention, without any propelling spring on the take up rod'or the reach rod, 1 utilize the brake power fully, since the only material resistance The renewal of brake shoes is also greatly facilitated, as the lever mechanism can be released very quickly, the release of the single take up rod releasing the brake shoes at both ends oi the car.

I claim as my invention:

1. In air-brake mechanism, the combination with the brake cylinder, its piston, the piston rod, and brake mechanism connected with the piston rod, of a reach rod having a slotted member in the path of the piston rod, thelength of the slot corresponding to the normal travel of the piston rod, a slide connected with the other end of the reach rod, a take up rod connected with the brake mechanism and on which said slide is adapted to move in one direction, a' clutch movable with the slide and constructed to couple it with the take up rod for movement in the opposite direction, and means for preventing movement 01' the take up rod in the other direction.

2. In air brake mechanism, the combination of the brake cylinder, its piston and piston rod, cylinder levers one of which is connected with said piston rod. a slack adjuster operated by the piston rod and arranged to shift the folcrum of the other cylinder lever when the piston exceeds its normal travel, a tie rod connecting the cylinder levers. live levers and rods connectingthem with the respective cylinder levers, dead levers fulcrumed 011 the car body and rods connecting them with the live levers, brake shoes con nected with the live levers and dead levers. a hand brake lever, operating connections therefrom to both ends of the car. and a slack connection from the hand brake lever to the piston rod.

3. In air brake mechanism, the combination of the brake cylinder, its piston and piston rod. cylinder levers one of which is connected with said piston rod. :1 slack adjuster operated by the piston rod and arranged to shift the fulcrum of the other cylinder lever when the piston exceeds its normal travel. a tie rod connecting the cylinder levers, live levers and rods connecting them with the respective cylinder levers, dead levers fnlcrumed on the car body and rods connecting them with the live levers, brake shoes connected with the live levers and dead levers, the arrangement of levers being similar at each end of the car. a hand brake lever, operating connections therefrom to both ends of the car, and a slack connection from the hand brake lever to the piston rod.

-.t. In air brake mechanism, the combination with the brake cylinder, its piston and piston rod. and brake mechanism connected with the piston rod. of a reach rod movable parallel with the piston and having two stops or engaging surfaces adapted to be engaged by the piston rod. the distance between said surf ,cs corresponding to the normal travel of the piston rod, and a slack adjuster operated by the movement of said reach rod.

5. In air brake mechanism, the combination of the brake cylinder. its piston and piston rod, brake actuating meclr anism, a pin for connecting said brake-actuating mechuu ism with the piston rod, and a slack adjuster having a member in the path of said pin and operated by an excess of travel of said pin.

6. In air brake mechanism, the combination of the brake cylinder, its piston and piston rod, brake actuating nieclr anism connected with said piston rod, hand brake mechanism having a connection allowing some play with the piston rod so that the hand brake mechanism may be operated without affecting the piston rod. and a slack adjuster arranged to be operated when the hand brake mechanism exceeds its normal travel.

7. In air brake mechanism, the combination of dead levers fnlcrumed on the car body and lever mechanism connecting said dead levers, with means for operating said lever mechanism and a slack adjuster arranged to be niechanically connected with said means when the latter exceeds its normal travel, said slack adjuster being also con nectcd with the mechanism intermediate between the two dead levers.

8. In air brake mechanism, the combination with the brake cylinder, its piston and piston rod and brake meclr anism operated thereby, of a take-up rod connected with the brake mechanism and movable in line with the piston rod, a reach rod relatively to which the piston has :1 limited independent movement after which the piston and reach rod move in unison to the same extent. and means for causing the reach rod and the take-up rod to move in unison and to the same extent in one direction while they are operatively connected.

in testimony whereof I have signed this specification in the presence of two subscribing witnesses.

RICHARD F. HAMILTON. 

